Abstract: A process for imprinting viewing fields on a cover glass is disclosed. First, the cover glass is annealed. A grid is then placed on the annealed cover glass. The grid has small openings which define the viewing fields. The annealed cover glass with a grid thereon is then coated with a thin film of an inert metal which can adhere to glass. The thin film is applied by way of a high vacuum coating method or a sputtering method. The grid is then removed from the coated cover glass. The coated cover glass is particularly useful in the preparation of microscope slides of filters having asbestos fibers or the like deposited thereon. A portion of the filter, which is smaller than the cover glass, is cut. The cut portion of the filter is placed onto either the coated cover glass or the microscope slide to form a filter combination. The filter combination is then cleared with a clearing solution. The filter combination is then fixed to the microscope slide or cover glass by means of a fixative.